Sand blasting apparatus



May 23, 1939. N. J. QUINN 2,159,051

SAND BLASTING APPARATUS Original Filed June 17, 1935 9&5. (7&6

g I I 4 INVENTOR.

ATTORNEYJ,

Patented May 23, 1939 PATENT OFFICE SAND BLASTING APPARATUS Nelson J.Quinn, Toledo, Ohio, assignor of onehalf to Horace B. Fay, ShakerHeights, Ohio Application June 17, 1935, Serial No. 27,033 RenewedAugust 18, 1938,

6 Claims.

The present invention, relating as indicated to sand blasting apparatus,is particularly directed to an'apparatus for mechanically projectingfinely divided bulk material, such as abrasive, for the purpose ofcleaning, coating or surfacing articles such as castings, sheets andvarious types of surfaces which must be cleaned or from which materialmust be removed rapidly and economically. The principal object of theinvention is the provision of a. simple apparatus of an impact type forprojecting finely divided material, which will be economical tomanufacture and to operate and sufficiently simple and light to allow itto be employed in portable form for the surfacing of objects, such forexample as railway cars, buildings, castings and the like, where thetool must be taken to the work. I To the accomplishment of the foregoingand related ends. said invention, then, consists of the meanshereinafter fully described and particularly pointed out in the claims;the annexed drawing and the following description setting forth indetail certain structure embodying the invention, such disclosed meansconstituting, however, but one of various mechanical forms in which theprinciple of the invention may be used.

In said annexed drawing:

Fig. l is a side elevation partially in section of my improvedapparatus;

Fig. 2 is a plan view of the same;

Fig. 3 is a transverse central section through one form of projectingmeans;

Fig. 4 is a side elevation of the means of Fig. 3;

Figs. 5 and 6 are a' front and side elevation respectively of anothertype of projecting means;

Fig. 7 is a front view of the projecting blade formed by the steps shownin Figs. 5 and 6; and Figs. 8 and 9 are a front elevation'and a planView of another type of projecting blade.

'Referring now to Figs. 1 and 2, my improved projecting apparatusconsists of a casing I, which is roughly semi-cylindrical in form and isprovided with a conduit 2 extending from substantially the centralportion of the casing and returning in a rebent portion 3 toward thecasing. At the end of the rebent portion 3 is inserted a conduit 4 whichterminates in the discharge nozzle 5 adjacent to the forward edge 6 ofthe casing. The conduit 4 has either inserted therein, or formed as apart thereof, a second conduit 1, through which finely divided materialmay be supplied to the terminal portion of the conduit 4 adjacent to thenozzle 5.

Mounted centrally of the semi-cylindrical casing l is a shaft l disposedin suitable bearings formed in the casing. Fixed on the shaft ID areprojecting blades which may take various forms. One form of blade isillustrated in Figs. 3 and 4 and consists of two circular sheet metaldiscs I l and 12 provided with a series of openings l3 and 14, eachseries of openings being arranged radially and there being a number ofsuch series disposed at equidistanct intervals around the disc adjacentits periphery. Mounted between the two discs are projectingblades properl5, which are merely rectangular strips of metal provided with lugs I6and I! at either side which engage and lock in the openings 13 and Mrespectively, in the two discs H and [2. These blades lock the two discstogether and constitute the abrasive engaging elements which project theabrasive from the casing.

The operation of the device as thus described is quite simple. When theshaft 10 is rotated it carries with it the discs I I and I2 and theblades l5. These blades move a considerable volume of air around in thecasing I and a large part of this air is projected tangentially into theconduit 2 and is then returned through the conduit 4 and nozzle to apoint directly in the path of the revolving blades. Finely dividedmaterial in the form of abrasive or other material is fed through theconduit 1 into the air stream flowing through the conduit 4 and is alsoprojected into the path of the revolving blades where it is picked up,and then struck with a force which depends upon the speed of rotation ofthe blades, their distance from the center of the shaft and the weightof the particles of material. A 6" to 8" disc of the construction shown,rotated at approximately 10,000 R. P. M. will impart a projection speedto the particles of the material of approximately 15,000 to 20,000 ft.,which is substantially the highest speed which is required for the mostsevere kind of work. Material thrown at this speed will rapidly removeenamel which has been baked on steel, will cut pitted rust from iron andsteel, and will out such materials as marble and granite with a veryconsiderable speed. At projection speeds between 8,000 and 12,000 feetother kinds of work, such as the cleaning of sand from castings, thesurfacing of such softer materials as brass, aluminum and the like, canbe very effectively carried out.

In the present apparatus there is of course movement of the materialover the inner surface of the conduit 1, the nozzle 5 and the forwardfaces of the blades l5, and in order to increase the life of these partsof the apparatus I coat all of these surfaces with a yieldable orflexible material, such as rubber. This rubber is applied to the metalby the process which is now generally used for bonding rubber to metaland gives a union between the two materials which is very much strongerthan that secured by cementing, and which is substantially a permanentunion between the rubber and metal.

It will be apparent that other types of projecting blades can beemployed instead of the one already described, and in Figs. 5, 6 and 7 Ihave shown one modification, and in Figs. 8 and 9 a second modificationof this part of the apparatus. Blades of the type shown in Fig. 7consist of a blade portion 20 provided with a split shank portion 2 Ithe two parts of the shank portion being secured to the spoke 22, whichin turn may be secured to the shaft l0. In forming a blade of this type,I start with a rectangular blank 23 of sheet metal, slit the same alongthe line 24 and then bend back the slit portions to form the two shanks2|, which then fit on either side of the spoke 22. This type of blademay also be faced with a compressible material 26 on its forwardsurface.

In Figs. 8 and 9 I have shown a blade consisting of a strip of sheetmetal 30 bent into angular form, one portion 3! being provided with boltholes for attachment to the end of a spoke 32 and the other portion 33being provided with a coating of compressible material, such as rubber,on its forward surface.

The present projecting apparatus is quite simple in construction,requires but few parts and these can all be of relatively light weight,so that it readily adapts itself for use as a portable tool. In this usethe shaft H3 may be operated either by a fractional horse power motor,which is secured directly to the casing l or by a flexible shaftconnected to the shaft is. For stationary use, where weight is not suchan important factor, a number of projecting elements can be assembledtogether on a shaft, a single casing can be employed to house all ofthese elements, and either separate nozzles for supplying abrasive toeach of the wheels individually can be used, or a common nozzle can beused for each two or three adjacent elements.

The present apparatus, which I have already referred to herein as of theimpact type, is thus referred to because I believe that the action whichoccurs in the machine involves the striking or batting of the particlesof abrasive in much the same manner as a bat strikes a ball, asdistinguished from the action which occurs in some types of mechanicalprojecting apparatus in which the abrasive particles are centrifugallythrown off from radially disposed passages in a rotating wheel. Theparticles of abrasive in the present apparatus are fed directly into thepath of the rotating blades and are projected in lines almost directlyat right angles to the path or direction of flow of abrasive as itleaves the discharge conduit and passes towards the blades. So far as Ihave observed theblades are in contact with the material onlymomentarily, and the action is substantially a striking or battingaction. Of course some material will be fed across the blades and willpossibly pass into the interior of the projecting elements and will thenbe discharged at various points. This portion of the discharge may betermed the wild discharge, but it represents only a minor part of thereal discharge and the great majority of the material applied to theblades is immediately struck and thrown along parallel lines and in thedirection above described.

It will be understood that while I have used the term abrasivethroughout the specification, this term is intended to denote eithermaterial such as sand or metallic grit, or other finely divided materialwhich may be employed to coat, surface, or otherwise treat the articleupon which the apparatus is employed.

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the mechanismherein disclosed, provided the means stated by any of the followingclaims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In apparatus of the character described, the combination of a shaft,a plurality of blades operatively mounted thereon, a casing enclosingsaid shaft and blades for not more than one-half of their circumference,a conduit leading from said casing and terminating closely adjacent theperiphery of said blades, said casing and said conduit being adapted toreceive and conduct a forced air stream from said blades, and means forfeeding abrasive into said conduit.

2. In apparatus of the character described, the combination of a shaft,spaced parallel discs mounted on said shaft, blades secured between saiddiscs, a casing enclosing said shaft and blades for not more thanone-half of their circumference, a conduit leading from said casing andterminating closely adjacent the periphery of said blades, and means forfeeding abrasive into said conduit.

3. In apparatus of the character described, the combination of a shaft,a plurality of blades operatively mounted thereon, av casing partiallyenclosing said blades, means for leading a portion of the air blastcreated by the rotary. movement of said blades and directing the sameradially inwardly toward said shaft, and means for supplying abrasive tosaid blast of air.

4. In apparatus of the character described, the combination of a shaft,a plurality of radially disposed blades cooperatively mounted thereon, acasing partially enclosing the said blades, a conduit leading from theperiphery of said casing and adapted to direct a portion of the airblast created by the rotation of said blades along a path dischargingclosely adjacent the outer edges of said blades toward said shaft, and asecond conduit extending into said first-named conduit for supplyingabrasive to the blast of air passing therethrough.

5. In apparatus of the character described, a shaft, a plurality ofblades carried on said shaft, a casing partially enclosing said blades,power operated means to rotate said shaft and blades to create an airblast, a feed pipe for abrasive positioned with an outlet openingadjacent the rotating blades, and means to direct a portion of the blastcreated by the rotating blades to the feed pipe to feed abrasive there--from into the path of the blades.

6. In apparatus of the character described, the combination of a shaft,spaced parallel disks mounted on said shaft, blades carried between saiddisks and rotatable therewith, an abrasive feed nozzle for directingabrasive between the disks and into the path of the rotating blades, arestricted portion and means for utilizing the windage effect of therotating blades to feed abrasive through the nozzle including a conduitleading from a region adjacent the periphery of the blades to theabrasive feed pipe.

NELSON J. QUINN.

